• 전자공학회논문지D
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• 제34D권3호
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• pp.114-122
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• 1997

The surface characteristics of polymers for liquid crystal alignment are studied by optical second-harmonic genertion (SHG) tecnique. Using SHG technique, the LC monolayers on rubbed polymer have already been studied. But, in this paper, the SH signals of polymer were observed and the orientational distribution of oriented polymer was studied. Te SHG experiments for side-chain type and main-chain type polymers are carried out as a function of rubbing strength. The orentational distribution of surface molecules of polymers is compared with the LC pretilt angle measured by the crystal rotation method.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.116-119
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• 1997

We investigated new type non-robbing liquid crystal (LC) alignment techniques in the cell with slanted non-polarized ultraviolet (UV) irradiation on polyimide (Pl) film. It is shown that the uniform alignment for nematic (N) LC is obtained by using slanted non-polarized UV irradiation on Pl surface. We successfully obtained that the pretilt ang1e of NLC is generated about 3 degree in the LC cells by using slanted non-polarized UV irradiation with 70 degree on Pl surface. We consider that the pretilt angle generation for NLC is attributed to interaction between the LC molecular and the PI surface. We conclude that the uniform LC alignment is attributed to anisotropic dispersion force effect due to photo depolymerization of polymer on Pl surface.

• 한국전기전자재료학회논문지
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• 제13권2호
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• pp.151-156
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• 2000

Effects of alignment layers on pretilt nagle generation and electrical characteristics in nematic liquid crystal(NLC) by using photo-alignment techniques on polyimide PI) surface with side chain were studied. The generated pretilt angle of the NLC on rubbed PI surface with 1-layer is almost the same as that with the 2-layers. However, the generated pretilt angle of the NLC on photo-induced PI surface with 2-layers is larger than that with the 1-layer. The different mechanism of pretilt generation in NLC was observed on the rubbing and photo-alignment method. Therefore, the pretilt angle of the NLC on photo-induced PI surface is attributed to surface roughness due to photo-dissociation on the polymer with UV light irradiation on PI surface. We observed the same characteristics of voltage-transmittance (V-T) and response time for 1- and 2-layers on PI surface. Consequently, we sugest that the VHR of photo-aligned TN-LCD is higher than that of the rubbing-aligned TN-LCD.

• 폴리머
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• 제29권4호
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• pp.413-417
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• 2005

LCD 배향막으로 응용하기 위하여 광반응성 polyvinylcinnamate 필름 위에서 액정 분자들의 배향에 관한 연구를 수행하였다. 선편광 UV를 polyvinylcinnamate 필름에 노광하면 선택적인 광반응에 의하여 필름 내에 이방성이 형성되고, 필름 표면에 인접한 액정 분자는 고분자와 분자간 상호작용으로 고분자 배향 방향과 동일한 방향으로 늘어선다. 광배향막을 사용한 액정 셀의 열 및 빛에 대한 안정성은 배향막에 UV를 다시 노광하고 열을 가한 후 유도된 액정 배향 변화를 측정하여 조사하였다. 선편광 UV를 여러번 노광한 필름의 경우 처음 노광 방향에 관계없이 최종으로 노광한 편광 UV의 방향에 따라 액정 배향이 유도되었다.

• Journal of Information Display
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• 제9권1호
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• pp.14-19
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• 2008

We demonstrated the capillary force lithography (CFL) method for controlling the azimuthal anchoring energy of a liquid crystal (LC) alignment layer. When a thermoplastic polymer film is heated to over the glass transition temperature, the melted polymer is filled into the mold structure by the capillary action and the aspect ratio of the pattern is determined by the dewetting time of the CFL process. Here, the proposed method showed that the azimuthal anchoring energy of the LC alignment layer could be simply controlled by the surface relief patterns which were determined by the dewetting times during the CFL patterning.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.189-192
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• 2005

We have investigated the EO characteristics generation of pretilt angle for a nematic liquid crystal (NLC) alignment with photoalignment method on three kinds of photopolymer surfaces using polymer substrates. The LC homogeneous alignment were observed on the PMI3CA (N-(phenyl)maleimide with 3-carbon chain cinnamoyl group) and PMIF (N-(phenyl)maleimide including fluoro cinnamoyl group). However, the homeotropic alignment on the PMI5CA(N-(phenyl)maleimide with 5-carbon chain cinnamoyl group) was obtained. Also, EO characteristics of the flexible photoaligned TN-LCD using PMIF surface are better than that of the flexible TN-LCD using PMI3CA surface. Also, the stable EO performances of flexible photoaligned VA-LCD using the PMI5CA surface was observed.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2009년도 춘계학술대회 논문집
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• pp.105-105
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• 2009

• E2M - 전기 전자와 첨단 소재
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• 제10권5호
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• pp.461-466
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• 1997

In this paper, we developed the new non-rubbing liquid crystal (LC) alignment techniques in the cell with slanted non-polarized ultraviolet (UV) light irradiation on polyimide (PI) film. It is shown that the uniform alignment for nematic (N) LC is obtained by using slanted non-polarized UV light irradiation on PI surface. We successfully obtained that the pretilt angle of NLC is generated about 3.3 degree in the cell with slanted non-polarized UV light irradiation with 70 degree on PI surface, for the first time. It is considered that the pretilt angle generation in NLC is attributed to interaction between the LC molecular and the PI, which is broken the polymer by slanted non-polarized UV irradiation. Therefore, we concluded that the uniform LC alignment is attributed to anisotropic dispersion force due to photo depolymerization with slanted non-polarized UV light irradiation on PI surface.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.545-548
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• 1999

The electro-optical characteristics of photo-aligned vertical-alignment (VA)-liquid crystal display (LCD) with non-polarized ultraviolet (UV) light irradiation of 45\`on homeotropic polyimide (Pl) surface were investigated. LC alignment on photo-aligned VA-LCD is attributed to photo-depolymerized reaction of the polymer with non-polarized UV light irradiation on PI surface. We had good voltage-transmittance (V-T) characteristics of photo-aligned VA-LCD. The response time of photo-aligned VA-LCD was slower than that of the rubbing-aligned VA-LCD. Finally, we suggest that the slow response time of photo-aligned VA-LCD depends on the LC domain.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.766-768
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• 2004

Rubbed films of a series of poly(p-phenylene 3,6-bis(4-(n-alkyloxy)phenyloxy)pyromellitimide)s (Cn-PMDA-PDA PIs), which are well-defined brush PIs composed of two aromatic-aliphatic bristles per repeat unit of a fully rodlike backbone, were investigated in detail using atomic force microscopy (AFM), optical retardation analysis and linearly polarized infrared (IR) spectroscopy in order to elucidate their surface morphology and molecular orientation. The liquid crystal (LC) alignment behavior and the anchoring energy of LC molecules on the rubbed films were also determined.